An Overview of BAV99 Switching Diode
26 December 2023
Ⅲ. What are the functions of BAV99 diode?
Ⅳ. Typical characteristics of BAV99 diode
Ⅴ. Technical parameters of BAV99 diode
Ⅶ. What is the difference between the electrostatic protection of BAV99 and TVS tubes?
BAV99 is a kind of switching diode. It takes shorter time than general diodes to change from on to off or from off to on. It is mainly used in switching circuits of electronic equipment, detector circuits, high frequency and pulse rectifier circuits and automatic control circuits. This article will provide you with an exhaustive guide to the BAV99, from functions and features to usage, to help you understand and apply this important component.
Switching diode is a kind of semiconductor diode, which is specially designed and manufactured for "on" and "off" on the circuit. It is from the conduction to cutoff or from cutoff to conduction time is shorter than ordinary diodes. Common switching diodes are 2AK, 2DK and other series, mainly used in electronic computers, pulse and switching circuits. The main function of a switching diode is to divide a circuit into two parts, one that conducts current when high (energized) and the other that cuts off completely when low (de-energized).
The BAV99 is a dual series switching diode. Manufactured by Onsemi, the BAV99 chip falls under the diodes category, boasting a compact design with dimensions measuring 2.92 mm in length, 1.3 mm in width, and 0.93 mm in height. Employing a surface mount device mounting style, this switching diode exhibits remarkable versatility with an operating temperature range spanning from -55°C to 150°C. The BAV99's impressive specifications further include a swift recovery time of 4ns, a forward voltage of 1.25V, and a minimal reverse current of 500nA. Additionally, it can handle a power dissipation of up to 225mW, making it a robust and reliable component for diverse electronic applications, particularly where efficient switching and diode functionality are paramount.
Alternative models:
• BAV70
• BAW56
• SBAV70
• MMBD1503
• Anti-over-voltage and negative pulse: When BAV99 is placed next to the IC, it effectively prevents damage to the IC from high over-supply voltage and negative pulse.
• Protection: Since the rear stage is the output terminal, it plays a protective role if the rear stage terminal is mistakenly inserted from the outside world, such as when the power supply unit.
• Limiting: Through the limiting function, BAV99 can effectively control the amplitude of the output signal to avoid overload and distortion and ensure the clarity and quality of the audio signal. In practice, the BAV99's limiting function is commonly used in mixing, audio editing and performance, which can effectively protect audio equipment from overload damage while improving sound quality and listening experience.
• Conducted immunity suppression: The placement of the BAV99 in the interface circuit section is intended to combat conducted immunity. When common-mode interference is coupled into the signal line through the interface circuit, it may trigger the appearance of high voltage in both directions. The addition of BAV99 can limit these voltages right at the interface, effectively reducing the voltage amplitude. However, it should be noted that once the external interference appears, a large noise will be generated on the positive voltage-clamped power supply, and similarly on the negative voltage-clamped ground. Therefore, in order to deal with these challenges more comprehensively, we usually recommend using the BAV99 in conjunction with an interface snubber filter.
TA=25°C unless otherwise noted
These ratings are limiting values above which the servicelly of any semiconductor device may be impaired.
Notes:
1. These ratings are based on a maximum junction temperature of 150°C.
2. These are steady state limits. The factory should be connected on applications involving pulsed or low duty cycle operations.
The factory should be connected on applications involving pulsed or low duty cycle operations.
1. Forward conduction voltage drop
When a BAV99 diode is in forward conduction, there is a pressure drop across the current flowing through the diode. The pressure drop is related to the forward current as well as the temperature. Generally the higher the silicon diode current, the higher the pressure drop. As the temperature increases, the pressure drop decreases.
2. Reverse leakage current
The BAV99 diode has some undesirable conditions in reverse cutoff. When subjected to backpressure, there is some small current that leaks from the cathode to the anode. Although this current is usually small, it has a higher reverse voltage and also a higher leakage current, resulting in a temperature rise. The leakage current in this case leads to increased losses, especially in high voltage environments.
3. Forward rated current
What is the current rating? For instance, in a 5 A/100V diode, the rated current is 5 A, serving as the primary nominal value for the diode. In theory, a BAV99 model diode, under square wave measurement conditions, may handle a larger DC current for silicon diodes, but this necessitates confirmation through specific test results. If the square wave aligns with the average DC current, it could potentially harm the BAV99 model diode. In the case of a 5A diode subjected to a 5A current, inadequate heat dissipation conditions can lead to elevated temperatures, thereby restricting the current passing through the BAV99 model diode based on the junction temperature.
4. Reverse voltage rating
When a BAV99 diode is cut off in reverse, if it can withstand a certain amount of reverse voltage, the maximum value of the reverse pressure is a fixed voltage. For example, for a 5A/100 volt BAV99 model diode, the current rating is 100 volts. However, to allow for some leeway, some manufacturers make a 100-volt BAV70 model diode, which can withstand 110 volts. Note, however, that there is no guarantee that the diode will operate stably when the rating is exceeded.
5. Forward inrush current
Under energized or other transient conditions, the diode needs to be able to withstand large inrush currents without damage. Naturally, this inrush current is not repeated or exists for a certain length of time between intervals. Typically, diode datasheets will contain test conditions and definitions for such inrush currents, which usually involve single sine or square wave currents, often up to several hundred amperes in value.
First, we need to mount the BAV99 on a suitable circuit board and make sure the connections are good. Then, as needed, we can connect it to other circuit components such as power supplies, signal sources, loads, etc. through appropriate resistors and capacitors. When using the BAV99, we need to follow the technical specifications and parameters of the BAV99 to ensure its proper operation and avoid damage. It is also important to note that the BAV99 has three pins, one of which is a common cathode and the other two are anodes respectively. When using it, we need to make sure that we connect the pins correctly to avoid problems such as short circuit or open circuit. At the same time, we also need to pay attention to the BAV99 switching voltage and switching speed and other parameters to ensure that it is suitable for specific application scenarios.
Numerous engineers prefer employing BAV99 for electrostatic protection applications, mistakenly assuming it can substitute for a TVS tube. However, this notion is incorrect, as BAV99 is a diode. Despite both diodes and TVS serving as safeguards against transient disturbances, their protective mechanisms differ.
Diode using the forward conduction characteristics, when the surge interference voltage is higher than the diode's forward conduction voltage, the diode conduction, the latter circuit is protected. TVS is the use of the principle of reverse breakdown for overvoltage protection of a special diode. TVS surge resistance, low operating voltage and start-up voltage, while the transient response time is also relatively fast, the junction capacitance is also relatively low. Diodes do not have the fast response and low clamp voltage characteristics of TVS. If you want to use a diode to protect a circuit from transients, it is recommended to choose a diode with a faster response time.
Frequently Asked Questions
1. What is a switching diode?
A switching diode is suitable for switching a small signal of up to 100 mA, acting as a rectifier. In contrast, a rectifier diode is used for AC line rectification (from alternating current to direct current). Switching diodes are designed to handle a voltage of less than tens of volts.
2. What is BAV99 used for?
The BAV99 is a widely used small signal device in dual diode configuration. Its two diodes in series can be used for any kind of signal processing, and two parts can even form a bridge for high speed full wave rectifying.
3. What is the operating temperature range of BAV99?
The operating temperature of BAV99 ranges from -55°C to 150 °C.
4. What is the through hole equivalent of BAV99?
Easybom also wants to remind you that the through-hole version of BAV99 is 1N4148 which we recently just talked about.
